Mild skin cleansing soap bar with hydrated cationic polymer skin conditioner

ABSTRACT

Disclosed is a mild skin cleansing soap bar composition comprising: (1) 50-90% soap, and (2) a hydrated cationic polymeric skin conditioner. The physical composition of the bar is such that the hydrated polymer is substantially uniformly distributed and well incorporated in the soap. The hydrated cationic polymer improves the mildness of the soap bar to a level approaching that of bars made with very mild synthetic surfactants, while maintaining the desirable physical characteristics of a pure soap bar without the polymer. 
     The preferred polymer is a hydrated cationic guar gum having a typical aqueous viscosity at 1% of from about 125 cps to about 3500±500 cps.

CROSS REFERENCE TO RELATED APPLICATIONS

This is a continuation of U.S. Ser. No. 119,284, filed Oct. 30, 1987,now U.S. Pat. No. 4,820,447, issued Apr. 11, 1989, which is acontinuation of U.S. Ser. No. 803,742, filed Dec. 2, 1985, nowabandoned.

TECHNICAL FIELD

This invention relates to skin cleansing soap bar compositionscontaining cationic polymers.

BACKGROUND OF THE INVENTION

The cleansing of skin with surface-active cleasning preparations hasbecome a focus of great interest. Many people wash and scrub their skinwith various surface-active preparations several times a day. Ideal skincleansers should cleanse the skin gently, causing little or noirritation, without defatting and overdrying the skin or leaving it tautafter frequent routine use. Most lathering soaps, liquids or bars failin this respect.

As background, reduced skin irritation benefits as measured by patchtesting of cationic and nonionic types of polymers are set out in"Polymer JR for Skin Care" Bulletin, by Union Carbide, 1977. Thecationic polymers are reported to be preferred over the other polymersbecause they provide better skin feel benefits.

Attention is directed to J.K.P. No. Sho 58 [1983] 167700, Ohata, et al.,which teaches a soap bar with 0.1-6% cationicpoly(diethyldiallylammonium chloride) and copolymers thereof. Ohata etal. appears to recognize a problem with the use of other cationicpolymers and teach away from the use of the other polymers includingJR400.

Attention is directed to U.S. Pat. No. 3,761,418, to Parran, Jr., issued9/25/73, which discloses detergent compositions containing particledeposition enhancing agents comprising a water-insolubleparticulate-cationic polymer mixture. Hydrated cationic guar gumpolymers are not mentioned. Parran, Jr.'s Example XV is a 50:50tallow/coconut (T/CN) fatty acid soap bar which contains 3% cationicpolymer. The preparation of the bar, however, is not specified. U.S.Pat. No. 4,012,341, to Orshitzer/Macander, issued 3/15/77, discloses anall-synthetic detergent shampoo bar comprising a mixture of anionic andnonionic detergents. The bars of Examples 2 and 4 contain 1% JR 400.Cationic guar gum polymers are not taught.

U.S. Pat. No. 4,338,211, Stiros, issued July 6, 1982, discloses a liquidskin cleanser with 2.3% to 3% of a synthetic surfactant, polymer JR-400,small amounts of free fatty acid, plus a fatty acid alkylolamide aslather boosting agents.

EPA 106,193, Turney, published 4/25/84, assigned to Union Carbide Corp.,teaches liquid skin cleansers with anionic detergent, fatty acid soapand cationic polymer. Soap bars are not taught in either Stiros orTurney.

UK Pat. Appln. GB2094307A, published 9/15/82, assigned to Johnson andJohnson Baby Products Co., discloses amphoteric-fatty acid complexes fordetergent products which exhibit good foam and low occular irritancy.This reference teaches that anionic surfactants should not exceed 20% toassure low occular irritancy. Cationic Polymer JR at levels of 0.5 to3.0% is taught. Liquids and bars are disclosed. Cationic guar gumpolymers are not disclosed and skin mildness is not discussed.

Attention is also directed to U.S. Pat. No. 4,234,464, to Morshauser,which issued 11/18/80. This reference discloses a detergent synbar inExample 6 which comprises: 45% isethionate, 5% alkyl amide, 37.5%stearic (C₁₈) acid, 5.0% hydrogenated tallow glycerides and 1% PolymerJR. This patent also discloses a wide range of synthetic surfactants andfatty materials. The synbars comprise up to 5% soap "without substantialdetriment" and up to 1.5% cationic polymer. Cationic guar gums are notmentioned.

U.S. Pat. No. 4,491,539, James J. Hoskins and Adriaan Kessler, issuedJan. 1, 1985, discloses liquid cleansing products comprising about 5% to30% of surfactant, about 0.1% to about 1.0% of guar material, about0.15% to about 1.0% of nonionic carboxyvinyl polymer, and water. Soapbar compositions are not disclosed. Another reference is British Pat.No. 2,103,236A, Colgate, Feb. 16, 1984, which discloses a liquiddetergent containing guar gum and a ternary surfactant mixture includinga betaine. Soap bar compositions are not disclosed. Also, British Pat.No. 2,114,994A, L'Oreal, Sept. 1, 1983, discloses a cleansing productbased on acylisethionates and cationic polymers. These products are notbased on soap.

Although it is known that cationic polymers provide hair and skinconditioning properties, none of the above references teach the use oflow levels of hydrated cationic guar gum polymers in a soap-based bar.None indicate that the important in-use soap bar characteristics (lathercharacter and volume, rinsing, soap bar feel, etc.) are preserved in thepresence of polymers. None indicate that the hydrated cationic guar gumpolymers must be well hydrated, incorporated and dispersed in the soapbar in order to achieve improved mildness while maintaining desirablesoap bar properties.

It was indeed surprising and unexpected that low levels of hydratedcationic guar gum polymers would provide mildness in a soap-based barthat is nearly equal to synbar products based on mild syntheticsurfactants, while maintaining desirable bar soap properties. It wasunexpected that the hydration of the cationic guar gum polymers wasnecessary in order to achieve good incorporation into the soap bar whichin turn leads to the mildness and maintenance of soap bar properties.

OBJECTS OF THE INVENTION

This invention relates to skin cleansing toilet bar compositions whichprovide improved skin mildness. Therefore, one object of this inventionis to provide a method of making a skin cleansing toilet bar compositioncomprising hydrated cationic polymers which exhibit improved skinmildness.

Another object of the present invention is the physical composition of askin cleansing toilet bar which has improved skin feel and mildnessbenefits and in which the polymer is well hydrated and uniformlydistributed in the soap bar.

Yet another object of the present invention is to provide for moreefficient utilization of a cationic skin conditioning agent in soapbars.

Other objects will become apparent from the detailed description below.

SUMMARY OF THE INVENTION

Disclosed is a mild skin cleansing soap bar composition comprising: (1)50-90% soap, and (2) a hydrated cationic polymeric skin conditioner. Thephysical composition of the bar is such that the hydrated polymer issubstantially uniformly distributed and well incorporated in the soap.The hydrated cationic polymer improves the mildness of the soap bar to alevel approaching that of bars made with very mild syntheticsurfactants, while maintaining the desirable physical characteristics ofsoap bars.

DETAILED DESCRIPTION OF THE INVENTION

Disclosed is a mild skin cleansing soap bar composition comprising: (1)50-90% soap, and (2) a hydrated cationic polymeric skin conditioner. Thephysical composition of the bar is such that the hydrated polymer issubstantially uniformly distributed and well incorporated in the soap.The hydrated cationic polymer improves the mildness of the soap bar to alevel approaching that of bars made with very mild syntheticsurfactants, while maintaining the desirable physical characteristics ofsoap bars.

Disclosed is a mild soap bar composition comprising:

(1) 50-90% soap; and

(2) an effective amount of a hydrated cationic polymeric skinconditioner uniformly distributed and incorporated in said soap bar,said cationic polymeric skin conditioner having a molecular weight offrom 1000 to 3,000,000, said cationic polymeric skin conditionercomprising a skin conditioning amount of a hydrated cationic guar gumhaving a 1-2% aqueous solution viscosity of from about 125 cps to about3500±500 cps at 25° C., wherein said aqueous solution has a pH of about9 to 11, and from 0% to about 5% of another cationic polymeric skinconditioner selected from the group consisting of:

(I) other cationic polysaccharides;

(II) cationic copolymers of saccharides and synthetic cationic monomers,and

(III) synthetic polymers selected from the group consisting of:

(A) cationic polyakylene imines,

(B) cationic ethoxypolyalkylene imines, and

(C) cationicpoly(N-(3-(dimethylammonio)propyl)-N'-(3-(ethyleneoxyethylenedimethylammonio)propyl)urea dichloride); and

(IV) mixtures thereof; and wherein said bar is substantially free ofunhydrated polymeric particles greater than 30 microns; and

(3) from about 7% to about 25% moisture.

The soap bar of this invention comprises at least 50% soap as itsprimary or sole surfactant and also contains as an essential ingredientan effective amount of a "hydrated" cationic polymer which significantlyimproves the mildness relative to a comparable soap bar without thehydrated polymer. The mildness achieved approaches that of productsbased on mild synthetic surfactants. Yet the bar maintains the highlyacceptable physical and in-use characteristics of a pure soap bar. Thepolymer is hydrated and uniformly dispersed and incorporated into thesoap bar. As used herein the term "cationic polymer" includes naturallyand synthetically derived cationic polymers. The abbreviation "CN" meanscoconut and "T" means tallow herein, unless otherwise specified. Allpercentages and proportions are by weight, unless otherwise specified.

The soap bar of this invention comprises about 1.2% to 5%, preferably1.2% to 2%, of a suitably hydrated cationic polymer having a molecularweight of from about 1000 to about 3,000,000, preferably one selectedfrom cationic guar gums having a molecular weight range of2,500-350,000.

The soap bar of this invention also comprises from about 50% to about90% soap, preferably at least 25% of tallow soap. The preferred bar ofthis invention comprises 50-80% T/CN fatty acid soap mixture.

A preferred soap bar of this invention also contains from about 2% toabout 17% moisturizer, preferably one selected from glycerin and freefatty acid or mixtures thereof. The more preferred bar of this inventioncontains at least 4% moisturizer.

In a method of making the bar of the present invention, the cationicpolymer is hydrated with water prior to mixing it with the soap duringthe soap bar making process. Hydration of the polymer produces, withsome cationic polymers, a fluid liquid. With other cationic polymers,e.g. cationic guar gum, a rigid gel is produced which can then bereduced to smaller particles. In either case the hydrated polymerincorporates into the soap mix readily and the polymer is distributeduniformly without significant numbers of nonhydrated polymer chunks. Theuniform distribution of the polymer maintains highly acceptable soap barin-use characteristics.

THE SURFACTANT

The fatty acid soaps which are essentials of this invention are alkalimetal soaps of fatty acids having alkyl chain lengths of C₈ -C₂₂,preferably C₁₂ -C₁₈, and especially those of the C₁₀ -C₁₄ chain lengthswhich are important in producing lather rapidly and of good, highlyacceptable quality. It is understood that coconut soap isinterchangeable with palm kernel oil soap. The fatty acid soaps arepresent at a level of 50-90%, preferably from 60-80%, and mostpreferably from 65-70%. The preferred soap has a ratio of tallow/coconutsoap of from 0.1:1 to 9:1, preferably from 1:1 to 1.5:1.

The soap bars of this invention can contain up to 20% of a syntheticsurfactant. If a synthetic surfactant is included, a mild one ispreferred. A mild synthetic surfactant is defined herein as one whichdoes relatively little damage to the barrier function of the stratumcorneum. The mild surfactant is present in the present composition at alevel of 0-20%, preferably about 2-15%. The fatty acid soap and mildsurfactant mixture preferably has a ratio of 2.5:1 to 37:1, preferablyfrom 2.5:1 to 14:1, and most preferably from 6.5:1 to 14:1,soap:synthetic.

Some preferred mild synthetic surfactants useful in this inventioninclude alkyl glyceryl ether sulfonate (AGS), anionic acyl sarcosinates,methyl acyl taurates, N-acyl glutamates, alkyl glucosides, acylisethionates, alkyl sulfosuccinate, alkyl phosphate esters, ethoxylatedalkyl phosphate esters, alkyl ether sulfates, methyl glucose esters,protein condensates, mixtures of alkyl ether sulfates and alkyl amineoxides, betaines, sultaines, and mixtures thereof. Included in thesurfactants are the alkyl ether sulfates with 1 to 12 ethoxy groups,especially ammonium and sodium lauryl ether sulfates. Alkyl chainlengths for these surfactants are C₈ -C₂₂, preferably C₁₀ -C₁₈. The mostpreferred mild surfactant is sodium CN AGS.

MOISTURIZERS/EMOLLIENTS

Moisturizers may be included to provide the skin conditioning benefitsand to improve the mildness of the product. The selection of the levelsand types of moisturizers to be incorporated into the product is madewithout adversely affecting the stability of the product or its in-usecharacteristics, thereby delivering good moisturization and lather.

The term "moisturizer" is often used within the cosmetic industrywithout very exact definition. The term is sometimes used as synonymouswith emollient, and is then meant to describe a material which imparts asmooth and soft feeling to the skin surface.

There are two ways of reducing water loss from the stratum corneum. Oneis to deposit on the surface of the skin an occlusive layer whichreduces the rate of evaporation. The second method is to addnonocclusive hygroscopic substances to the stratum corneum which willretain water, and make this water available to the stratum corneum toalter its physical properties and produce a cosmetically desirableeffect. Nonocclusive moisturizers also function by improving thelubricity of the skin.

Both occlusive and nonocclusive moisturizers are suitable for use in thepresent invention. Some examples of moisturizers are long chain fattyacids, liquid water-soluble polyols, glycerin, propylene glycol,sorbitol, polyethylene glycol, ethoxylated/propoxylated ethers of methylglucose (e.g., methyl gluceth-20) and ethoxylated/propoxylated ethers oflanolin alcohol (e.g., Solulan-75).

When moisturizers are used in the compositions of the present inventionthey are used at levels of from about 2% to about 20% by weight of thecomposition. The preferred and more preferred levels of moisturizersare, respectively, 4% to 15% and 8% to 12%. The preferred moisturizersare the coconut and tallow fatty acids. Some other preferredmoisturizers are the nonocclusive liquid water-soluble polyols (e.g.,glycerin) and the essential amino acid compounds found naturally in theskin. The most preferred moisturizer is a mixture of coconut fatty acidand glycerin having a ratio of from 2:1 to 0.5:1, coconut fattyacid:glycerin.

The total surfactant (i.e., soap plus any synthetic surfactant, if used)to moisturizer ratio is preferably 4:1 to 39:1 and, more preferably, 9:1to 20:1, surfactant:moisturizer.

Other preferred nonocclusive moisturizers are compounds found to benaturally occurring in the stratum corneum of the skin, such as sodiumpyrrolidone carboxylic acid, lactic acid, urea, L-proline, guanidine andpyrrolidone. Examples of other nonocclusive moisturizers includehexadecyl, myristyl, isodecyl or isopropyl esters of adipic, lactic,oleic, stearic, isostearic, myristic or linoleic acids, as well as manyof their corresponding alcohol esters (sodium isostearoyl-2-lactylate,sodium capryl lactylate), hydrolyzed protein and other collagen-derivedproteins, aloe vera gel and acetamide MEA (acetmonoethanolamide).

Other examples of both occlusive and nonocclusive types of moisturizersare disclosed in "Emollients--A Critical Evaluation," by J. Mausner,Cosmetics & Toiletries, May 1981, incorporated herein by reference.

THE CATIONIC POLYMER

The cationic polymeric skin conditioning agent essential in the presentinvention is selected from the group consisting of:

(I) cationic polysaccharides;

(II) cationic copolymers of saccharides and synthetic cationic monomers,and

(III) synthetic polymers selected from the group consisting of:

(A) cationic polyakylene imines

(B) cationic ethoxy polyalkylene imines, and

(C) cationicpoly[N-[-3-(dimethylammonio)propyl]-N'-[3-(ethyleneoxyethylenedimethylammonio)propyl]urea dichloride].

The amount of hydrated cationic polymeric skin conditioners found usefulin the composition of the present invention is from about 0.2% to about5%, preferably from about 0.5% to about 2%, based on the weight of theunhydrated polymer. The bar soap composition containing these relativelysmall amounts of polymer delivers significantly improved clinicalmildness relative to a composition without the polymer. The resultantmildness approaches that of synthetic-based skin cleansing products. (Itis known that certain synbars are generally milder than those based onsoap, particularly the lower chain length fatty acid soaps.) Themildness improvement is further demonstrated by an improved barrierfunction of the stratum corneum relative to a product without polymer,as determined by measurement of transepidermal water loss. The cationicpolymers used in this invention also provide a desirable silky, soft,smooth in-use feeling. It is believed that the positively chargedpolymer combines with the negatively charged sites on the skin toprovide a soft skin feel after use.

The cationic polymers employed in this invention achieve the mildnessbenefit while maintaining the highly acceptable and desirable in-usesoap bar characteristics of lather character and creaminess, lathervolume, rinsing, skin feel, odor, bar feel, etc. This is unexpectedsince cationic polymers, particularly when used at the higher levelstypically necessary for a mildness improvement and when used without thehydration specified by the present invention, have a significantnegative impact on in-use characteristics. For example, they cansuppress lather volume and alter its character, result in grainy bartexture, result in poor rinsing, and have negative impact on odor.

For the compositions of the present invention, it is important that thecationic polymer be evenly distributed throughout the soap bar.Hydration of the cationic polymer is essential to the achievement ofuniform distribution. Some cationic polymers are commercially availablein a prehydrated form, while others are commercially available only intheir unhydrated form. Uniform distribution of the polymer in the barenables the polymer to readily deposit on skin to improve clinicalmildness. This distribution helps in the maintenance of the highlyacceptable soap bar in-use characteristics (skin feel, good lather, barsmoothness and avoidance of bar cracking upon drying out).

(I)

The cationic polysaccharide class encompasses those polymers based on 5or 6 carbon sugars and derivatives which have been made cationic byengraphing of cationic moieties on the polysaccharide backbone. They maybe composed of one type of sugar or of more than one type, i.e.copolymers of the above derivatives and cationic materials. The monomersmay be in straight chain or branched chain geometric arrangements.Cationic polysaccharide polymers include the following: cationiccelluloses and hydroxyethylcelluloses; cationic starches andhydroxyalkyl starches; cationic polymers based on arabinose monomerssuch as those which could be dervied from arabinose vegetable gums;cationic polymers derived from xylose polymers found in materials suchas wood, straw, cottonseed hulls, and corn cobs; cationic polymersderived from fucose polymers found as a component of cell walls inseaweed; cationic polymers derived from fructose polymers such as Inulinfound in certain plants; cationic polymers based on acid-containingsugars such as galacturonic acid and glucuronic acid; cationic polymersbased on amine sugars such as galactosamine and glucosamine; cationicpolymers based on 5 and 6 membered ring polyalcohols; cationic polymersbased on galactose monomers which occur in plant gums and mucilages;cationic polymers based on mannose monomers such as those found inplants, yeasts, and red algae; cationic polymers based on thegalactomannan copolymer known as guar gum obtained from the endosperm ofthe guar bean.

Specific examples of members of the cationic polysaccaride class includethe cationic hydroxyethyl cellulose JR 400 made by Union CarbideCorporation; the cationic starches Stalok® 100, 200, 300 and 400 made byStaley, Inc.; the cationic galactomannans based on guar gum of theGalactasol 800 series by Henkel, Inc. and the Jaguar Series by CelaneseCorporation.

(II)

The cationic copolymers of saccharides and synthetic cationic monomersuseful in the present invention encompass those containing the followingsaccharides: glucose, galactose, mannose, arabinose, xylose, fucose,fructose, glucosamine, galactosamine, glucuronic acid, galacturonicacid, and 5 or 6 membered ring polyalcohols. Also included arehydroxymethyl, hydroxyethyl and hydroxypropyl derivatives of the abovesugars. When saccharides are bonded to each other in the copolymers,they may be bonded via any of several arrangements, such as 1,4-α;1,4-β; 1,3-α; 1,3-β and 1,6 linkages. The synthetic cationic monomersfor use in these copolymers can include dimethyldiallylammoniumchloride, dimethylaminoethylmethyacrylate, diethyldiallylammoniumchloride, N,N-diallyl,N-N-dialkyl ammonium halides, and the like. Apreferred cationic polymer is Merquat 550 prepared withdimethyldialkylammonium chloride and acrylamide monomers.

Examples of members of the class of copolymers of saccharides andsynthetic cationic monomers include those composed of cellulosederivatives (e.g. hydroxyethyl cellulose) and N,N-diallyl,N-N-dialkylammonium chloride available from National Starch Corporation under thetradename Celquat.

(III)

The cationic synthetic polymers useful in the present invention arecationic polyalkylene imines, ethoxypolyalklene imines, andpoly[N-[3-(dimethylammonio)propyl]-N'-[3-(ethyleneoxyethylenedimethylammonio)propyl]urea dichloride] the latter of which is availablefrom Miranol Chemical Company, Inc. under the trademark of Miranol A-15,CAS Reg. No. 68555-36-2.

Preferred cationic polymeric skin conditioning agents of the presentinvention are those cationic polysaccharides of the cationic guar gumclass with molecular weights of 1,000 to 3,000,000. More preferedmolecular weights are from 2,500 to 350,000. These polymers have apolysaccharide backbone comprised of galactomannan units and a degree ofcationic substitution ranging from about 0.04 per anhydroglucose unit toabout 0.80 per anhydroglucose unit with the substituent cationic groupbeing the adduct of 2,3-epoxypropyltrimethyl ammonium chloride to thenatural polysaccharide backbone. Examples are JAGUAR C-14-S, C-15 andC-17 sold by Celanese Corporation, which trade literature reports have1% viscosities of from 125 cps to about 3500±500 cps. In order toachieve the benefits described in this invention, the polymer must havecharacteristics, either structural or physical which allow it to besuitably and fully hydrated and subsequently well incorporated into thesoap matrix.

It is noteworthy that the cationic guar gums JAGUAR C-14-S and C-15 arepurposely designed by the supplier to hydrate slowly. This slowhydration feature is believed to be necessary for the typical uses ofthese guar materials in shampoos and conditioners, where prematurehydration and subsequent viscosity growth are detrimental to theformulation process.

The cationic guar gum polymers useful in the present invention have beenfound to be more effective skin conditioners than those cationicpolymers based on hydroxyethyl cellulose (e.g., JR-400 commerciallyavailable from Union Carbide Corporation) also useful in the presentinvention and referred to in U.S. Pat. No. 3,761,418, to Parran, Jr.,supra, and in UK Pat. Appln. GB2094307A, supra. Solutions of cationicpolymers JAGUAR C-14-S and JR-400 and which contained an anionicsurfactant (sodium laurate soap) were evaluated. Skin condition wasmeasured via visual evaluations of dryness and redness and viainstrumental assessment of skin condition (transepidermal water loss,skin hydration, and sonic attenuation.) Results indicated the cationicguar gum to be about twice as effective as JR-400. Thus, cationic guargum is a more efficient skin conditioner than ahydroxyethylcellulose-based cationic polymer and is the most preferredtype of cationic polymer for use in the present invention.

The usual optionals can be used in the composition of the presentinvention, e.g., perfumes and electrolytes may be used in formulatingthe skin cleansing products, generally at a level of about 0.1% to about2.5% of the composition. Colorants, and also fillers such as talc andclay, may also be used. Preservatives, e.g., EDTA, generally at a levelof less than 1% of the composition, may be incorporated in the cleansingproducts to prevent microbiological growth. Antibacterials can also beincorporated, usually at levels up to 1.5%.

HYDRATION OF THE POLYMER

The hydrated cationic polymer of this invention is a polymer which hasabsorbed at least a sufficient amount of water so that it can besubstantially uniformly distributed into a soap bar. Preferably theamount of water used for hydration should not be in excess of the amountneeded to obtain uniform dispersion of the polymer in the soap, sinceexcess water must be removed during the processing of the soap.

In the present invention, the hydrated polymer is substantiallyuniformly distributed and well-incorporated into the soap bar. Thehydrated polymer in a soap bar can be identified by either of thefollowing evaluations.

1. MICROSCOPIC EVALUATION

Hydrated polymers in a soap bar exhibit a characteristic pattern whenviewed with a light microscope in the presence of the cationicsubstantive sulphan blue dye and photographed on color film. That is,the photographs show a uniform coloration of a blue/green hue, due to apolymer/dye complex. The blue/green coloration due to the polymer/dyecomplex is observed as being uniform in a soap bar sample containing thehydrated polymer. The area of coloration is preferred to be at least 90%of the sample. Within the polymer-containing regions, the intensity ofthe color can be variable from one location to another. Additionally,there are very few nonhydrated polymer particles in the photographedfield of the microscope. The number of particles in a 264 cm² area of afield of 77×magnification is less than 100, preferably less than 40, andmore preferably less than 10. The visible particles in the soap bars ofthis invention are about 30 microns or smaller.

Procedure for Microscopic Evaluation

The uniformity of the polymer distribution is assessed using amicroscopic evaluation of bars which have been treated with a cationicsubstantive blue dye. The procedure is outlined as follows:

1. A thin section of the bar is cut and it is approximately 2 cm×1.5 cmand 2-3 mm thick.

2. The section is placed on a microscope slide.

3. A small amount of about 0.1% alcohol-based sulphan blue dye solutionis applied to the surface of the section for approximately 30 seconds.

4. The excess dye is then washed off with isopropanol and the barsurface gently dried with compressed air.

5. The stained sections are viewed using a light microscope and eitheroverhead lighting, side lighting, or bottom lighting at magnificationsgenerally of 50-500×.

6. The images are recorded in color on photographic film and developedfor viewing.

7. The polymer appears as a blue or green color in the photographs.Uniformity of polymer distribution is assessed and the presence ofnonhydrated polymer particles is determined.

2. VISUAL TACTILE EVALUATIONS

Hydration of the polymer can be judged during the soap making process byexamination of the soap mix after the polymer has been added and mixedfor at least 15 minutes (and before the drying step). It is preferredthat no lumps of polymer be visible to the eye during this examination.Additionally, the feel of the resultant bars must not be gritty orgrainy upon evaluation in water.

The cationic guar gum polymers require a relatively large amount ofwater for their hydration. The amount of water is believed to be relatedto molecular weight whereby higher molecular weight polymers requiremore water. The preferred ratio of water to polymer for JAGUAR C-15 isabout 9 parts water to 1 part polymer. For JAGUAR C-14-S, the ratio isabout 19 parts water to one part polymer. The amount of water requiredto hydrate a polymer is determined experimentally and is believed to bea function of polymeric molecular weight. The molecular weight of C-14-Sis about 200,000 to 300,000 and the molecular weight of C-15 is lowerand thereby requires less water.

Polymer Hydration

The cationic polymer can be hydrated in water prior to its addition tothe soap making process or it can be added to the soapmaking process ata point when there is sufficient water present in the process to hydratethe polymer. In summary, the methods of adding the polymer to the soapmaking process include the following:

(1) the incorporation of a prehydrated cationic polymer into a crutchermix (typically 25-40% water) which can include other soap baringredients;

(2) direct injection mixing of a prehydrated cationic polymer into aliquid soap stream formulation prior to the soap stream entering adryer;

(3) dry addition of a well-granulated cationic polymer directly to acrutcher mix of soap containing sufficient water to hydrate the polymer;the crutcher mix can include other soap bar ingredients.

(4) prehydration of polymer with an aqueous solution of a syntheticsurfactant prior to mixing with soap in the crutcher; and

(5) preparing an aqueous slurry of the polymer (i.e. with insufficientwater to fully hydrate the polymer) followed by direct injection mixingof the polymer slurry into a liquid soap formulation stream which inturn contains sufficient water to hydrate the polymer, prior to the soapstream entering the dryer.

A nonlimiting example of a method of cationic polymer hydration isillustrated in Example 1.

EXAMPLE 1

1. 100 g JAGUAR C-15 (powder) are quickly added to 900 g of very coldwater (ca. 40°-50° F., 4°-10° C.) which is agitated with a turbine blademixer.

2. The blend is mixed for 10-15 minutes until it becomes very viscous.

3. The mixture is stored at 140° F. (60° C.) for 12-24 hours to furtherfacilitate hydration. (Storage temperatures from about ambient to evenhigher than 140° F. can be used in this step). At Step (3) this hydratedpolymer is a rigid gel.

Process for Making a Mild Cleansing Composition Based on Soap

In general, procedures common to conventional toilet soap bar making areemployed. The hydrated polymer is introduced into an aqueous soapmixture prior to vacuum drying. Typically prior to the drying step thesoap mix will have a moisture content of 25% to 40%. In the drying stepthat moisture level is reduced to ca. 7% to 25% preferably 7% to 15%.The following example utilizes polymer incorporation.

EXAMPLE 2 Crutching Step

About 127.6 parts of a mix containing: 29.8% moisture, 52.7% 50/50tallow/coconut (T/CN) soap, 16.7% CN AGS paste, 3.3% coconut free fattyacid (CNFA), 3.1% glycerin, and 0.2% NaCl are heated to ca. 150°-200° F.(65°-94° C.). About 10.0 parts of the hydrated polymer JAGUAR C-15 madein accordance with the procedure of Example 1 are mixed in.

Vacuum Drying Step

The crutcher mix is vacuum dried at ca. 50 mm Hg absolute pressure toreduce the moisture content of the mix to ca. 10% and to plod this soapinto noodles. These noodles are passed through a milling step once.

Amalgamating Step

The once-milled soap noodles are weighed and placed in a batchamalgamator. To about 99.1 parts noodles in the amalgamator are added:0.20 part TiO₂, 1.4 parts perfume, 0.15 part colorant solution, 0.15part of a solution which contains ca. 40% EDTA. The combined ingredientsare mixed thoroughly.

Milling Step

Three-roll soap mills are set up with all rolls at 85°-105° F. (29°-41°C.). The mixture from the amalgamator is passed through the millsseveral times to obtain a homogeneous mix. This is an intimate mixingstep.

Plodding and Stamping Steps

A conventional plodder is set up with the barrel temperature at about90° F. (32° C.) and the nose temperature at about 110° F. (43° C.). Theplodder used is a dual stage twin screw plodder that allows for a vacuumof about 40 to 65 mm Hg between the two stages. The soap log extrudedfrom the plodder is typically round or oblong in cross-section, and iscut into individual plugs. These plugs are then stamped on aconventional soap stamping apparatus to yield the finished toilet soapbar.

The formulation of the finished bar of this example is set out below asExample 2.

EXAMPLES 2-6

    ______________________________________                                                   Example:                                                                      2     3       4       5     6                                      ______________________________________                                        Base Soap    66.3%   66.9%   66.9% 66.9% 77.9%                                (50T/50CN)                                                                    Alkyl Glyceryl Ether                                                                       10.0    10.0    10.0  10.0  --                                   Sulfonate                                                                     Coconut Fatty Acid                                                                         5.6     4.0     4.0   4.0   4.0                                  Water        10.0    10.0    10.0  10.0  10.0                                 Glycerin     4.0     4.0     4.0   4.0   4.0                                  NaCl         1.0     1.0     1.0   1.0   1.0                                  JAGUAR C-15  1.0     2.0     1.0   1.0   1.0                                  JR-400       --      --      1.0   --    --                                   Merquat 550  --      --      --    1.0   --                                   Minors (Perfume,                                                                           2.1     2.1     2.1   2.1   2.1                                  Color, etc.)                                                                  ______________________________________                                    

The details of the preparation of Example 2 are set out above. Examples3-6 are all prepared similar to Example 2, but for the ingredientdifferences set out in the above table. In Examples 4 and 5, othercationic polymer, JR-400 and Merquat 550 are respectively added inaddition to the cationic guar gum JAGUAR C-15. Prehydrated polymerswhich are not too viscous, e.g., Merquat 550, can be added either in thecrutcher or in the amalgamator, as long as uniform distribution isachieved. It should be noted that the JAGUAR C-15 in Example 6 is about1.2% of polymer based on the weight of the solid soap.

A bar made in accordance with the procedure of Example 2 was examinedunder magnification in accordance with the dye test previously describedherein, and was found to have uniform polymeric distribution with veryfew remaining discrete particles of nonhydrated cationic guar gum orother cationic polymer.

Other bars were made in accordance with the procedure set out in Example2 except that unhydrated C-14-S cationic guar gum was added at theamalgamation step. They were observed to be nonuniform and contained anumber of large chunks of polymers, which were as large as 120 microns.

Clinical Assessment of the Toilet Bars

The clinical test procedure used to evaluate several toilet barformulations for skin mildness is given below.

Clinical Mildness Arm Wash Test Procedure (4 Washes Per Day for TwoWeeks for 40 Washes)

The washings were performed by the panelists. Each panelist was assigneda set of two test products for washings. These bars were all kept (inplastic dishes) under technical personnel control. The test procedurefor each arm is:

1. Pick up and wet a Masslin towel.

2. Pick up and wet the bar.

3. Rub the bar on the towel for 6 seconds.

4. Put bar aside and rub the towel on the inner forearm from wrist areaup to elbow and back down again. Repeat up-down cycle for 10 seconds.

5. Allow lather to remain on for forearm for 90 seconds.

6. Rinse thoroughly for 15 seconds with warm water.

7. Pat dry with paper towel.

8. Wait 5 minutes.

9. Repeat Steps 1-7 above.

10. Return 3-4 hours later to repeat Steps 1-9 above.

Test Product Formulations

The formulations of the products tested clinically are given in Table 1.Composition X is a soap-based control product without polymer.Composition Y is a control product based on synthetic surfactants.Composition B corresponds to Example 2 above. Composition "A" was madein accordance with the procedure set out in Example 2 like Composition"B", but a different cationic guar gum polymer was used and 19 parts ofwater per 1 part of polymer was required. Composition "X" is a controlsoap bar without polymer, and Composition "Y" is believed to be thecomposition of DOVE®, a prior art benchmark for toilet bar mildness.

                  TABLE 1                                                         ______________________________________                                        Test Product Formulations                                                     Composition     X       Y        A    B                                       ______________________________________                                        Na Soap 50/50 T/CN                                                                            67.3%   --       66.3 66.3                                    H.sub.2 O       10.0    7.0      10.0 10.0                                    Glycerin        4.0     --       4.0  4.0                                     Free CN Fatty Acid                                                                            5.6     2.5      5.6  5.6                                     Na C.sub.12 AGS 10.0    --       10.0 10.0                                    NaCl            1.0     1.35     1.0  1.0                                     Minors (Perfume,                                                                              2.1     1.45     2.1  2.1                                     Color, etc.)                                                                  Na Soap 85/15 T/CN                                                                            --      11.7     --   --                                      Na CN Igepon    --      44.0     --   --                                      Stearic Acid    --      26.0     --   --                                      Na C.sub.12 Alkyl Benzene                                                                     --      1.8      --   --                                      Sulfonate                                                                     Na Stearate     --      2.4      --   --                                      Na Isethionate  --      2.6      --   --                                      JAGUAR C-14-S   --      --       1.0  --                                      JAGUAR C-15     --      --       --   1.0                                     ______________________________________                                    

Clinical Test Skin Grading Scales

The forearm skin grading scales reported herein are set out below.

Forearm Grading Scale Skin Dryness

0--Perfect skin.

1.0--Patches of checking and/or slight powderiness and occasionalpatches of small scales may be seen. Distribution generalized.

2.0--Generalized slight powderiness. Early cracking or occasional smalllifting scales may be present.

3.0--Generalized moderate powderiness and/or moderate cracking andlifting scales.

4.0--Generalized heavy powderiness and/or heavy cracking and liftingscales.

5.0--Generalized high cracking and lifting scales. Eczematous change maybe present. Powderiness may be present but not prominent. May seebleeding crack.

6.0--Generalized severe cracking. Eczematous change may be present.Bleeding cracks may be present. Scales large, may be beginning todisappear.

Forearm Grading Scales

    ______________________________________                                        Skin Erythema      Skin Smoothness                                            ______________________________________                                        0   No redness       0     Very high smoothness/slick                         1.0 Barely detectible redness                                                                      1.0   Extreme smoothness                                 2.0 Slight redness   2.0   Substantial smoothness                             3.0 Moderate redness 3.0   Moderate smoothness                                4.0 Heavy or substantial                                                                           4.0   Slight smoothness                                      redness                                                                   5.0 Severe redness   5.0   Barely detectible smoothness                       6.0 Extreme redness  6.0   No smoothness                                      ______________________________________                                    

The term "generalized" as used herein means that more than 50% of thesurface area of the forearm exhibits the attribute. Whole unit skingrades reflect generalized condition. Half units are used to representintermediate conditions.

Clinical Test Results

The clinical mildness test results expressed in terms of skin grades fordryness, erythema, and smoothness are shown below in Table 2. Example Xis a control product without polymer. Example Y is a control productbased on a mild, commercially available synbar, DOVE®.

                  TABLE 2                                                         ______________________________________                                        Paired Comparison Skin Grades                                                 One Week            Two weeks                                                        Smooth-  Ery-    Dry-  Smooth-                                                                              Ery-  Dry-                               Example                                                                              ness     thema   ness  ness   thema ness                               ______________________________________                                        Y      1.82     1.98    2.00  3.02   3.28  3.30                               X      1.98     2.42    2.40  3.20   3.66  3.70                               Differ-                                                                              -0.16**  -0.44*  -0.40*                                                                              -0.18  -0.38*                                                                              -0.40*                             ence                                                                          (Y - X)                                                                       B      1.92     2.21    2.52  2.91   3.28  3.31                               X      2.08     2.58    2.79  3.24   3.65  3.65                               Differ-                                                                              -0.15**  -0.36*  -0.27*                                                                              -0.33* -0.37*                                                                              -0.33*                             ence                                                                          (B - X)                                                                       A      2.10     2.38    2.25  2.90   3.17  3.29                               X      2.23     2.33    2.15  3.35   3.44  3.58                               Differ-                                                                              -0.13**  0.058   0.10  -0.44* 0.27* -0.29*                             ence                                                                          (A - X)                                                                       ______________________________________                                         *Significant difference at 95% or greater confidence level.                   Difference: "+" (second treatment better) "-" (first treatment better)        **Significant difference at 89-94% confidence level.                     

For smoothness, erythema and dryness, lower numbers indicate better skincondition (see the grading scale set out above). Specifically, in Table2, for the pair represented by Examples B and X, Example B of thisinvention has a dryness grade of 3.31, which is lower than the drynessgrade of 3.65 for Example X. See Table 1 for the formulations. Thedifference is calculated as dryness of B minus dryness of X and is-0.33. Therefore, a negative number indicates that the first treatmentis better.

                  TABLE 3                                                         ______________________________________                                        Single Product Skin Grades                                                    ______________________________________                                        Grade*        Product (vs. Test Product Code)                                 ______________________________________                                        Dryness                                                                       2.98          Example X (Soap Control)                                        2.61          Example B (1% C-15)                                             2.52          Example Y (DOVE ®)                                          2.52          Example A (1% C-14-S)                                           ______________________________________                                        Grade         Product (vs. Test Product Code)                                 ______________________________________                                        Erythema                                                                      3.20          Example X                                                       2.87          Example B                                                       2.78          Example Y                                                       2.56          Example A                                                       Smoothness                                                                    1.85          Example X                                                       1.72          Example Y                                                       1.54          Example B                                                       1.38          Example A                                                       ______________________________________                                         *Reported as change from initial condition.                              

These Paired Comparative data of Table 2 show that the skin cleansingcompositions of this invention (Examples A and B) result insignificantly improved mildness over control soap Example X without anypolymer in terms of dryness, erythema and smoothness as shown by theabove lower grades. See the grading scales set out above. It should benoted that relatively low levels of polymer, 1%, achieved these results.In addition, the Single Product analysis of Table 3 indicates thatExample A of this invention is directionally better than Example Y basedon mild surfactants. Example B approaches this synbar for mildness also.

What is claimed is:
 1. A mild soap bar composition comprising:(1) 50-90%soap; and (2) and effective amount of a hydrated cationic polymeric skinconditioner uniformly distributed and incorporated in said soap bar,said cationic polymeric skin conditioner having a molecular weight offrom 1000 to 3,000,000, said cationic polymeric skin conditionercomprising from about 0.2% to about 5% of a hydrated cationic guar gumhaving a 1-2% aqueous solution viscosity of from about 125 cps to about3500±500 cps at 25° C., wherein said aqueous solution has a pH of about9 to 11, and from 0% to about 5% of another cationic polymeric skinconditioner selected from the group consisting of:(I) other cationicpolysaccharides; (II) cationic copolymers of saccharides and syntheticcationic monomers, and (III) synthetic polymers selected from the groupconsisting of:(A) cationic polyakylene imines, (B) cationicethoxypolyalkylene imines, and (C) cationicpoly(N-(3-(dimethylammonio)propyl)-N'-(3-(ethyleneoxyethylenedimethylammonio)propyl)urea dichloride); and (IV) mixtures thereof;andwherein said bar is substantially free of unhydrated polymericparticles greater than 30 microns; and (3) from about 7% to about 25%moisture.
 2. The mild soap bar composition of claim 1 wherein saidcomposition comprises: from about 50% to about 80% of surface activeagent selected from soaps and mixtures of soap and synthetic surfactantswherein said soap is present at a level of at least 50% and saidsynthetic surfactant can be present up to a level of 20% by weight ofsaid composition; and from about 0% to about 20% of a moisturizer. 3.The mild soap bar composition of claim 1 wherein said soap comprisesfatty acid soaps having fatty acid carbon chain lengths of C₈ -C₂₂. 4.The mild soap bar composition of claim 1 wherein said bar contains atleast 25% tallow soap.
 5. The mild soap bar composition of claim 1wherein said soap is a mixture of tallow and coconut soaps having aratio of 0.1:1 to 9:1.
 6. The mild soap bar composition of claim 5wherein said ratio is 1:1 to 1.5:1.
 7. The mild soap bar composition ofclaim 1 wherein said composition contains from about 2% to about 20% ofa synthetic surfactant selected from alkyl glyceryl ether sulfonates,anionic acyl sarcosinates, methyl acyl taurates, N-acyl glutamates,alkyl glucosides, acyl isethionates, alkyl sulfosuccinates, alkylphosphate esters, ethoxylated alkyl phosphate esters, methyl glucoseesters, protein condensates, mixtures of ethoxylated alkyl sulfates andalkyl amine oxides, betaines, sultaines, the alkyl ether sulfates with 1to 12 ethoxy groups, and mixtures thereof, wherein said syntheticsurfactants contain C₈ -C₂₂ alkyl chains.
 8. The mild soap barcomposition of claim 7 wherein said synthetic surfactant has an alkylchain length of C₁₀ -C₁₈.
 9. The mild soap bar composition of claim 1wherein said composition contains up to 20% of a C₁₀ -C₁₈ alkyl glycerylether sulfonate.
 10. The mild soap bar composition of claim 1 whereinsaid composition contains from about 2% to about 17% moisturizer. 11.The mild soap bar composition of claim 1 wherein the other cationicpolysaccharide polymer is cationic hydroxyethylcellulose polymer.
 12. Amethod of making a mild soap bar in accordance with claim 1 comprisingthe steps of:(1) hydrating an effective amount of said cationic guar gumpolymer with water, and (2) uniformly distributing and incorporating thehydrated cationic guar gum polymer into an aqueous soap mix whereby saidhydrated cationic guar gum polymer is substantially uniformlydistributed and incorporated in said aqueous soap mix, and (3) dryingsaid uniform mix to a moisture level of from 7% to 25%, and (4) formingthe dried product obtained by step (3) into a bar shape.
 13. The methodof making a mild soap bar in accordance with claim 12 wherein saidcationic polymer is hydrated in a soap making crutcher step.
 14. Themethod of claim 12 wherein said polymer is hydrated with water prior tomixing with said aqueous soap mix.
 15. The method of claim 12 whereinsaid hydrated polymer is a free flowing liquid and is injected into aliquid soap stream prior to drying.
 16. The method of claim 12 whereinsaid hydrated polymer is a cationic guar gum gel which is mixed in asoap crutcher step mixture containing 25% to 40% water.
 17. The methodof claim 12 wherein said bar has a moisture level of 7% to 15%.